1. Field of the Invention
This invention relates to a nailing gun, more particularly to a nailing gun incorporating an improvement relating to a nail pusher.
2. Description of the Related Art
Referring to FIGS. 1 to 3, a nail driving gun generally includes a nail shooting nose 100 connected to a barrel 200 and a nail magazine 300. The nail shooting nose 100 includes a base plate 101 and a face plate 102. First and second safety plates 401, 402 are disposed between the base and face plates 101 and 102. The nail magazine 300 has a nail pusher plate 301 which serves to push a nail stick (not shown) placed within the nail magazine 300 toward the base plate 101. The base plate 101 has a nail outlet 106 to receive a nail fed to the base plate 101.
The first and second safety plates 401, 402 are secured to each other. A safety member 403 has one end 404 extending in to a hole 406 formed in the first safety plate 401 through a hole 108 of the base plate 101, and another end 405 connected to an actuating plate 407 which in turn is connected to a valve rod 408 that controls a pneumatically operated nail driving mechanism mounted within the barrel 200. A trigger 409 is provided to activate the actuating plate 407.
When no nail shooting operation is performed, the end 405 of the safety member 403 is biased by a spring (not shown) so that the first and second safety plates 401, 402 are pushed by the end 404 of the safety member 403 to protrude outwardly of the base plate 101 and the face plate 102. When a nail shooting operation is performed, the nail shooting nose 100 is pressed against a site to be nailed. As a result, the first and second safety plates 401 and 402 are pushed upward so that the safety member 403 depresses the actuating plate 407. In this situation, the pressing of the trigger 409 will activate the actuating plate 407 and the valve rod 408 so that a nail is driven outward from the nail shooting nose 100.
When the nails in the nail magazine 300 are used up, the nail pusher plate 301 moves to the base plate 101 with a front end 302 thereof protruding into a slot 400 of the first safety plate 401 through an aperture 107 of the base plate 101 so that the first and second safety plates 401, 402 cannot move upward even when the nail shooting nose 100 is pressed against a site to be nailed. As such, the driving mechanism of the nailing gun is prevented from performing idly a nail shooting operation.
Typically, a nail pusher for pushing a nail stick toward a nail shooting nose is loaded with one or more springs which are mounted within a nail magazine. Referring to FIGS. 4 and 5, a conventional nail magazine 11 includes a magazine base 112 and a magazine cover 113 which is coupled with the magazine base 112 by sliding over and interlocking with the magazine base 112. A nail pusher 12 is movably mounted on the magazine cover 113, and springs 13 are connected to the nail pusher 12 and the magazine cover 113. The nail pusher 12 and the springs 13 are received slidably in a nail channel 111 defined by the magazine base 112 and the magazine cover 113. When a nail stick 2 is placed in the nail channel 111, the springs 13 are placed in a compressed state so that the nail stick 2 is urged by the springs 13 to move toward a base plate 114 of a nail shooting nose.
However, since the springs 13 are exposed to the nail channel 11 without any accompanying limiting element, the springs 13 are prone to wobble and deformation. In addition, dusts and debris can intrude into the clearances in the springs 13 due to frequent opening of the nail magazine 11, thus adversely affecting the sliding movement of the nail pusher plate 12. Therefore, protection of the springs from contaminating substances is desirable in order to maintain good performance of the springs 13 and the nail pusher 12.